{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:57:16Z","timestamp":1760241436731,"version":"build-2065373602"},"reference-count":22,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2018,4,2]],"date-time":"2018-04-02T00:00:00Z","timestamp":1522627200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["MTI"],"abstract":"<jats:p>The number of webpages in the Internet has increased tremendously over the last two decades however only a part of it is indexed by various search engines. This small portion is the indexable web of the Internet and can be usually reachable from a Search Engine. Search engines play a big role in making the World Wide Web accessible to the end user, and how much of the World Wide Web is accessible on the size of the search engine\u2019s index. Researchers have proposed several ways to estimate this size of the indexable web using search engines with and without privileged access to the search engine\u2019s database. Our report provides a summary of methods used in the last two decades to estimate the size of the World Wide Web, as well as describe how this knowledge can be used in other aspects\/tasks concerning the World Wide Web.<\/jats:p>","DOI":"10.3390\/mti2020012","type":"journal-article","created":{"date-parts":[[2018,4,2]],"date-time":"2018-04-02T12:32:20Z","timestamp":1522672340000},"page":"12","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Webometrics: Some Critical Issues of WWW Size Estimation Methods"],"prefix":"10.3390","volume":"2","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3988-087X","authenticated-orcid":false,"given":"Srinivasan","family":"Mohana Arunachalam","sequence":"first","affiliation":[{"name":"Faculty of Informatics and Mathematics, University of Passau, 94032 Passau, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2661-7749","authenticated-orcid":false,"given":"Adamantios","family":"Koumpis","sequence":"additional","affiliation":[{"name":"Faculty of Informatics and Mathematics, University of Passau, 94032 Passau, Germany"}]},{"given":"Siegfried","family":"Handschuh","sequence":"additional","affiliation":[{"name":"Faculty of Informatics and Mathematics, University of Passau, 94032 Passau, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,2]]},"reference":[{"key":"ref_1","unstructured":"Rhodenizer, D., and Trudel, A. 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